CN108430878B

CN108430878B - Can end with venting feature

Info

Publication number: CN108430878B
Application number: CN201680072324.3A
Authority: CN
Inventors: 克里斯托夫·保罗·拉姆齐; 托马斯·亚历山大·格罗夫斯; 安东尼·查尔斯·弗朗格
Original assignee: Crown Packaging Technology Inc
Current assignee: Crown Packaging Technology Inc
Priority date: 2015-12-09
Filing date: 2016-12-08
Publication date: 2020-03-20
Anticipated expiration: 2036-12-08
Also published as: GB2545403B; AU2016366496B2; HUE055273T2; ES2870008T3; GB201521700D0; GB2545403A; ZA201803811B; SG11201804382QA; JP2018536592A; US10703533B2; EP3386878B1; AU2016366496A1; BR112018011566B1; CA3007522A1; CO2018006523A2; CN108430878A; SA518391714B1; CA3007522C; EP3386878A1; US20180362209A1

Abstract

A metal end for joining to a metal container body. The end portion includes an outer curl, a central panel within the outer curl, and a tab having a longitudinal axis (a). The end portion further comprises a rivet securing the tab to the central panel, and a score in the central panel having two spaced apart end portions defining a hinge therebetween, the hinge being located to one side of said longitudinal axis (a), whereby operation of the tab ruptures the score and causes the area of the central panel within the score to pivot about the hinge and provide an aperture in the central panel. The score extends into a region of the center panel behind a centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis (a) and on the other side of the longitudinal axis (a) from the hinge.

Description

Can end with venting feature

Technical Field

The present invention relates to a can end having venting features to increase flow rate. The invention also relates to a can provided with such a can end.

Background

Most metal beverage cans on the market today are two-piece cans, comprising a one-piece can body having a can end joined to an open end. Further, the most common type of can end is the type of can end known as a "stay-on-tab" end. The stay on tab end includes a tab that is lifted by a consumer's fingers to create a rupture along a score line defining an aperture. Once opened, the tab is pressed back against the end and remains attached to the can end. Can ends of this type have been manufactured by crown holdings gmbh to

Produced for some years for brand names.

For some applications, it is more desirable to increase the liquid flow rate through the orifice of the can end. For example, in restaurants and coffee shops, increasing the liquid flow rate through the orifice of the can end is beneficial for quickly emptying the contents of the can into a drinking glass. Consumers drinking directly from the can also find this advantageous. Can ends that avoid so-called "gurgling" during pouring are also satisfactory.

Crown Holdings, Inc. utilizes a brand name

The known can end solves these problems. 360End is an End adapted to close a can body having an opening with an inner diameter of about 52mm (also referred to as a 202 diameter neck, where 202 nominally represents 2 and 2/16 inches over the seam when the can is joined), and to allow substantially the entire center panel of the End to be removed when the End is open. Crown also produces Global Vent under the brand name^TMAs is known, the end has a dual orifice opening mechanism to facilitate smoother pouring from the beverage can, enhancing the user experience. The consumer simply opens the beverage can as usual, rotates the tab to align it over the button-like depression to the right of the main opening, and then presses down to activate the second aperture. The secondary aperture provides a vent that allows air to flow into the can as product flows out of the primary aperture. Although Global Vent^TMThe end provides excellent performance, but it requires an additional opening step compared to conventional ends.

In addition to these Crown Holdings limited can ends, other manufacturers have or have attempted to market can ends that claim to be advantageous for increasing flow rates and/or gurgling resistance.

While at first glance it would seem obvious to increase the size and/or shape of the orifice to increase the flow rate and avoid gurgling sounds, this is not trivial. Any practical design must maintain ease of opening the conventional end and maintain a level of pressure performance. Additionally, in a very competitive field, any new can end design should not significantly increase production costs.

US20150329238 is about a beverage can end with a supplemental venting feature.

Disclosure of Invention

According to a first aspect of the present invention, a metal end for joining to a metal container body is provided. The end portion includes an outer curl, a central panel within the outer curl, and a tab having a longitudinal axis (a). The end portion further comprises a rivet securing the tab to the central panel and a score in the central panel having two spaced apart end portions defining a hinge therebetween, the hinge being located to one side of said longitudinal axis (a), whereby operation of the tab ruptures the score and causes the region of the central panel within the score to pivot about the hinge and provide an aperture in the central panel. The score extends into a region of the central panel behind a centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis (a) and on the other side of the longitudinal axis (a) from the hinge.

When the tab is fully lifted and the aperture is opened, the tab may be in substantially the same rotational orientation relative to a rotational axis provided by a rivet employed by the tab.

The end portion may include a chuckwall between the curl and the center panel, and, optionally, a countersink (countersink) between the chuckwall and the center panel. Alternatively, there may be no countersink between the center panel and the chuckwall.

At least 0.5%, preferably at least 1%, of the area of the central panel within the score may be rearward of and on the other side of the longitudinal axis (a) from the hinge, the centerline (B) extending through the center of the rivet and perpendicular to said longitudinal axis (a).

The score is at least 0.5mm, preferably at least 1mm, behind the centre line (B) and on the other side of the longitudinal axis (a) from the hinge, the centre line (B) extends through the centre of the rivet and is perpendicular to said longitudinal axis (a).

The vent radius on the score on the other side of the longitudinal axis (a) from the hinge, behind the centre line (B) extending through the centre of the rivet and perpendicular to said longitudinal axis (a), may be in the range from 2mm to 6mm, preferably in the range from 2.5mm to 5 mm.

The end may be a 47mm or smaller end, optionally a 43mm or smaller end.

The end pour orifice may have a length of 14mm or less and a flow rate of greater than 30 ml/sec.

The end may have a generally flat panel with localized features to absorb excess material resulting from the formation of the score and rivet, but without a counter-sunk groove conventionally used to stiffen the end panel.

According to a second aspect of the present invention, there is provided a container comprising a metal container body and a metal end according to the first aspect described above, the end being joined to an opening of the metal container body for closing the metal container body.

Although the score on the central panel of the can has been described with reference to the longitudinal axis (a) of the tab, other axes may of course be defined for this purpose. Some of these alternative definitions are set forth in the exemplary embodiments below.

In an exemplary embodiment of the invention, there is a metal end for joining to a metal container body. The end is formed by a housing having an axis of mirror symmetry. The end portion includes an outer curl, a center panel inside the outer curl, and a tab. The end further includes a rivet securing the tab to the center panel, the rivet being located on an axis of symmetry, and a score in the center panel, the score having two spaced apart ends defining a hinge therebetween, the hinge being located to one side of the axis of symmetry, such that operation of the tab ruptures the score and causes an area of the center panel within the score to pivot about the hinge and provide an aperture in the center panel. The score extends into a region of the center panel rearward of the centerline (B) and on the other side of the axis of symmetry from the hinge. A centre line (B) extends through the centre of the rivet and is perpendicular to the axis of symmetry.

In another exemplary embodiment of the invention, there is a metal end for joining to a metal container body. The end portion includes an outer curl, a center panel inside the outer curl, and a tab. The end further includes a rivet securing the tab to the center panel, the rivet being offset from the midpoint of the center panel, and a score in the center panel, the score having two spaced apart ends defining a hinge therebetween, the hinge being located on one side of a longitudinal axis defined between the rivet and the midpoint of the center panel, whereby operation of the tab ruptures the score and causes an area of the center panel within the score to pivot about the hinge and provide an aperture in the center panel. The score extends into a region of the center panel behind a centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis and on the other side of the longitudinal axis from the hinge.

In another exemplary embodiment of the invention, there is a metal end for joining to a metal container body. The end portion includes an outer curl, a center panel within the outer curl, a countersink having an axis of mirror symmetry, and a tab. The end further includes a rivet securing the tab to the center panel, the rivet being located on the axis of symmetry, and a score in the center panel, the score having two spaced apart ends defining a hinge therebetween, the hinge being located to one side of the axis of symmetry, whereby operation of the tab ruptures the score and causes the area of the center panel within the score to pivot about the hinge and provide an aperture in the center panel. The score extends into a region of the center panel rearward of a centerline (B) extending through the center of the rivet and perpendicular to the axis of symmetry and on the other side of the axis of symmetry from the hinge.

In another exemplary embodiment of the invention, there is a metal end for joining to a metal container body. The end portion includes an outer curl, a center panel inside the outer curl, and a tab. The end further includes a rivet securing the tab to the center panel and a score in the center panel, the score having two spaced apart ends defining a hinge therebetween, the hinge being located on one side of a longitudinal axis defined between a point on the rivet and the score on opposite sides from the rivet, the point being selected such that the longitudinal axis intersects the score at a right angle, whereby operation of the tab ruptures the score and causes an area of the center panel within the score to pivot about the hinge and provide an aperture in the center panel. The score extends into a region of the center panel behind a centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis and on the other side of the longitudinal axis from the hinge.

Drawings

Fig. 1 and 2 schematically illustrate a known, seamless beverage can end;

FIG. 3 is a perspective view of the seamless can end of FIGS. 1 and 2;

figures 4 and 5 schematically illustrate a seamless can end according to a first embodiment of the invention;

FIG. 6 is a perspective view of the seamless can end of FIGS. 4 and 5;

FIG. 7 illustrates certain key features of a known can end;

fig. 8 to 10 illustrate an end portion of a container of the type joined to a metal can according to a second embodiment of the present invention.

Detailed Description

FIG. 1 shows a top view of a known brand name produced by Crown Holdings, Inc

Stay on tab ends (seamless) for launch into the market. The end is formed by first pressing a disc, typically of aluminum material, using a press called a "shell press". This process creates various features in the disc including an outer curl 1, a chuck wall 2 radially inward of the curl 1, an anti-peaking bead ("countersink") 3 that is concave outward radially inward of the chuck wall 2, and a center panel 4. The shell press also forms a continuous reinforcing bead 5 in the central panel. Other features may also be formed by the shell press but are not described herein. When the end is produced by a shell press, it is referred to as a "shell".

The finished shells are fed to a laminator called a "converting laminator". The converting press presses the score 6 into the intermediate panel. The score 6 has a residual depth of about 0.091mm along most of its length, but has a break 7 on one side. The score 6 is discontinuous with a break in the left hand region of the rivet. An upwardly projecting rivet 8 is formed in the middle of the middle panel 4 and a tab 9 is fixed to the rivet.

The finished end is joined to the filled can body. As can be seen in fig. 1, the product is opened by the consumer inserting his or her fingers under the rightmost end of the tab and prying the tab upward. This action causes the nose of the tab, identified in the figures as reference numeral 10, to be pressed down against the region of the middle panel within the score 6, first causing the score to break at a point radially inward of the nose. The score residue increases over a portion of the score profile such that resistance to rupture is increased. The shallow region of the score is called the "stopper" and typically has two depths: a medium depth region of about 2.5mm to 5mm away from the rivet, and a full depth region of about 5mm to 7.5mm away from the rivet. The mid-depth zone had a score residual of about 0.132mm and the full-depth zone had a score residual of about 0.150 mm.

The initial rupture causes the interior of the can to vent and the rupture extends rapidly around the score line to the stopper. This creates a large enough orifice to safely vent the headspace. Thus, when the user has completely ruptured the stopper, the canister is substantially fully vented. Continued prying of the tab and further pressing of the tab nose into the can results in the fracture extending clockwise around the score until it reaches the end and eventually causes the panel within the score to bend around the break 7 which acts as a hinge, thereby opening the aperture and allowing the contents to be poured.

Fig. 2 is a schematic illustration of the end of fig. 1, highlighting the tab 9, the score line 6 and the outer edge of the rivet 8. Figure 2 shows a broken line a indicating the longitudinal axis (or centre line) of the tab 9. A break line ("centerline") B is perpendicular to the longitudinal axis a and passes through the center of the rivet 8. As is clear from fig. 2, to any significant extent, the score 6 does not extend beyond the rivet 8 or behind the rivet 8 on the side of the rivet opposite the hinge 7. In other words, the score 6 does not extend to a portion below the longitudinal axis a and to the right of the centerline B as shown in the figures.

Figure 3 is a perspective view of the can end known from figures 1 and 2.

Figures 4 and 5 illustrate can end constructions that can provide improved flow rates. Features of the end portion common to the end portion of figure 1 are shown with like reference numerals. The relevant change relates to the score 14, the score 14 now extending to the portion of the central panel 4 to the right of the rivet centre line B, in that area which is below the longitudinal axis of the tab a. The percentage of the aperture panel defined by the score line below axis a and to the right of centerline B is significant, e.g. more than 0.5% and preferably more than 1.0%. The score physically extends to the right of the centerline at a distance of preferably at least 0.5mm, more preferably at least 1.0 mm. Conventionally, the score line is actually about 1mm to the left of the centerline. (Note that moving the score to the right of the centerline is not generally considered a developmental option, as it might be thought that this would result in failure during opening-because the score does not propagate naturally along such a path and the opening operation would fail during venting and/or subsequent opening of the orifice.)

It has been found that the radius of the score in the region of the venting feature is important to achieve the venting feature. The radius should be greater than 2mm (preferably 2.5mm) to provide smooth score propagation and less than 6mm (preferably 5mm) to create a discrete venting feature over the major portion of the orifice.

It should be noted that the only changes to the end relate to the location and size of the score 14. The ends are otherwise conventional. As such, the only change to the production line requirements is a change to the tooling that created the score. This is a relatively small change to be made. Figure 6 is a perspective view of the can end of figures 4 and 5.

Experiments have shown that for the 202 end, although the increase in orifice area due to the configuration illustrated in fig. 3 and 4 (in the case of the 202 end) is about 10.4%, the flow rate through the orifice increases by 36%. This is surprising and significant. Conventionally, the flow rate from the orifice is proportional to the area. The inventors believe that the reason for the non-linear flow behaviour is due to the significantly increased height of the orifice, which provides a portion of the orifice where air can easily enter back into the tank during pouring. The venting feature improves outflow flow speed and smoothness of the pour, with less tendency for the flow to purring during outflow. Indeed, the improvement in flow rate is so great that the consumer is very likely to be aware of the difference, meaning that cans incorporating the improved end will be sharply distinguished relative to cans having a conventional end.

The following performance tests have been performed on the improved end:

ejection and tear forces;

aging and bond buckle pressure testing;

safe venting at high internal pressures; and

open after storage under high pressure when the end is capped.

The results have demonstrated that the performance of the improved end is not reduced in any of these respects.

A comparison of the ends of fig. 1-3 and 4-6 shows that for the latter the score around the venting feature has a tighter radius of curvature followed by a shallow stop. The stop is shallow in fig. 5 indicated by reference numeral 16, followed by a bend indicated by reference numeral 17. By way of example, for a conventional 202 end, the radius of curvature of the score immediately following the stop may be on the order of 5 mm. For the improved ends described herein, the radius of curvature may be around 4mm or even 3 mm. As discussed above, the detent shallow is a portion of the score that has a shallower depth than the remainder thereof. As such, shallow stops tend to provide greater resistance to rupture during initial venting. A further surprising advantage of the improved can end is that the tighter radius of curvature of the portion 17 provides greater resistance to rupture. Due to the increased resistance, in some embodiments, to make the score easier to open, the score residual in the stopper 16 may be increased. In some cases, the stop features may all be removed together, i.e., the depth of the score 14 is substantially constant along its entire length. The advantage of removing the stop is that the production and maintenance of the production tool is simpler.

Table 1 below illustrates the comparative dimensions and flow rates for the conventional 202 end and for the 202 end with the improved design (4mm and 3mm radius of curvature). Percentage changes are also indicated where appropriate. Dimensions are all in millimeters and flow rates are given in milliliters/second.

The above discussion assumes that for a given can end size, e.g., 202, we want to achieve an increased flow rate. However, for a given flow rate, the present invention also facilitates a reduction in can end diameter. In addition to the use of smaller volume cans, reduced can end size is also desirable for the use of so-called "metal bottles". Such metal bottles have a shape similar to glass bottles, with a longer and thinner neck than conventional metal cans. A narrower opening of a metal bottle typically requires an end size of 45mm or less. Manufacturers have been challenged to manufacture ends for metal bottles using designs based on conventional stay-on pull-ring type ends, particularly for end sizes less than 45 mm.

Figure 7 schematically illustrates a central panel of a 45mm can end designed for use with a metal bottle. FIG. 7 indicates a number of key design criteria, including:

panel length-this is the length of the orifice panel that is open at the end;

finger entry length-this is the length of the area into which a consumer can insert his or her fingers to lift the tab;

lift length-this is the length of the tab between its radially outermost point and the opposite inside of the rivet;

beak length-this is the length of the tab between the beak of the tab and the inside of the rivet (where the tab is attached to the rivet platform forming the hinge);

countersink-this is the width of the countersink.

In order to make easy opening possible, the finger entry length should be at least 8 mm. Lowering the length below it makes it difficult for some consumers to access the end of the tab. It is also important to maintain a suitable ratio of lift length to beak length, and a suitable ratio of panel length to beak length. Further, once opened, when the tab is perpendicular to the center panel, the point of contact of the tab with the panel should be maintained so that the hinged position of the orifice panel is fully opened, thereby allowing the entire product to be discharged.

The inventors have conducted "pour" tests to demonstrate that an improved flow rate end can use a panel length of about 1.5mm less than a conventional orifice panel length, which is the distance across the orifice measured in the direction of axis B. This reduced aperture length, in turn, allows for the use of a reduced beak length to effectively open the aperture. The beak length may be reduced by about 0.5mm, which allows for a reduced tab lift length to effectively open the score. The lifting length is reduced by about 1.7 mm. Thus, the possible reduction in the total panel diameter is about (1.5mm +1.7mm)3.2 mm.

The reduction in panel diameter leads to further possibilities. Since smaller panels are inherently stiffer, it is possible to omit the countersink. A countersink is typically provided to increase the hardness of the end. The removal of the countersink provides at least a further 4mm savings in the diameter of the end. Thus, for the same flow rate, the total savings is around 7.2 mm. For the same flow rate, the conventional 200-mm end (50mm) can be replaced with a 47mm end (with a countersink) or a 43mm end (without a countersink). The change from 200 ends to 43mm ends achieves dramatic metal savings.

Fig. 8 illustrates an improved design of end 20 suitable for closing a metal bottle. Fig. 9 shows the end joined to the metal can body 21, and fig. 10 shows a perspective view of a vertical cross section through the joined end and can body of fig. 9.

It is noted that not only are embodiments of the present invention useful in enabling the production of metal bottles and achieving increased flow rates, they may also be used to reduce the failure rate of conventional can designs. The force applied to the underside of the region within the score is proportional to the area of the region. By reducing the area, the force is reduced and the likelihood of the area within the score separating during opening and "launching" is reduced. In other words, smaller orifice sizes may reduce failure rates. Additionally, or alternatively, embodiments may reduce harsh tool requirements, particularly for scoring tools, as the tolerance allowed for scoring may be increased.

It will be appreciated by those skilled in the art that various modifications could be made to the above-described embodiments without departing from the scope of the invention.

TABLE 1

Claims

1. A metal end for joining to a metal container body, the metal end comprising:

outward curling;

an outer curled inner central panel;

a tab having a longitudinal axis (A);

a rivet securing the tab to the center panel;

a score in the central panel, the score having two spaced apart ends defining a hinge therebetween, the hinge being located to one side of said longitudinal axis (A) when the tab is in its normal unopened orientation, whereby operation of the tab ruptures the score and causes the area of the central panel within the score to pivot about the hinge and provide an aperture in the central panel,

wherein the score extends into the region of the central panel behind a centre line (B) extending through the centre of the rivet and perpendicular to the longitudinal axis (a) and on the other side of the longitudinal axis (a) from the hinge.

2. The metal end of claim 1 including a chuck wall between the outer curl and the central panel.

3. The metal end of claim 2 including a countersink between the chuckwall and the center panel.

4. The metal end of claim 2 wherein there is no countersink between the center panel and the chuckwall.

5. The metal end of any preceding claim wherein at least 0.5% of the area of the central panel within the score is behind a centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis (a) and on the other side of the longitudinal axis (a) from the hinge.

6. The metal end of claim 5 wherein at least 1% of the area of the central panel within the score is rearward of the centerline (B) and on the other side of the longitudinal axis (A) from the hinge, the centerline (B) extending through the center of the rivet and perpendicular to the longitudinal axis (A).

7. The metal end according to any one of claims 1-4 wherein the score is at least 0.5mm behind the centerline (B) and on the other side of the longitudinal axis (A) from the hinge, the centerline (B) extends through the center of the rivet and is perpendicular to the longitudinal axis (A).

8. The metal end of claim 7 wherein the score is at least 1mm behind the centerline (B) and on the other side of the longitudinal axis (A) from the hinge, the centerline (B) extends through the center of the rivet and is perpendicular to the longitudinal axis (A).

9. The metal end according to any one of claims 1-4 wherein the vent radius behind the centre line (B) extending through the centre of the rivet and perpendicular to the longitudinal axis (A) and on the score on the other side of the longitudinal axis (A) from the hinge is in the range from 2mm to 6 mm.

10. The metal end according to claim 9, wherein the vent radius behind the centre line (B) extending through the centre of the rivet and perpendicular to the longitudinal axis (a) and on the score on the other side of the longitudinal axis (a) from the hinge is in the range from 2.5mm to 5 mm.

11. The metal end according to any one of claims 1-4, wherein the metal end is circular and has a diameter of 47mm or less.

12. The metal end according to any one of claims 1-4, wherein the metal end is circular and has a diameter of 43mm or less.

13. The metal end of any one of claims 1-4 wherein the metal end pour orifice has a length of 14mm or less and a flow rate greater than 30 ml/sec.

14. A container comprising a metal container body and a metal end according to any one of claims 1-13, said metal end being joined to an opening of the metal container body for closing the metal container body.